(1) Field of the Invention
The present invention relates to a press-contact electrical interconnector used for interconnecting a liquid crystal display and a circuit board or interconnecting circuit boards, and an improvement of the method for producing the same.
(2) Description of the Prior Art
There are various kinds of press-contact electrical interconnectors, but recently a U-shape metal line interconnector has been used for interconnecting a liquid crystal display and a circuit board or interconnecting circuit boards. The U-shaped metal line interconnector comprises, as shown in FIG. 1, an insulative foam elastomer 15 formed into a block having a section roughly in a half oval shape by using a sponge silicone rubber material; an insulative rubber sheet 2A having a section roughly in a U shape attached to the surface, a curved one side and the backside on the periphery of the insulative foam elastomer 15 by covering them; and a plurality of conductive threads 3 bonded and secured in a U shape on the surface of the insulative rubber sheet 2A and provided in proximity in a row arrangement in parallel at equal pitches in the direction of from one end face to the other end face of the insulative foam elastomer 15s.
The metal line interconnector in a U shape constructed in this manner is pressed against and clamped between an unillustrated electrode of an electronic circuit board, serving as an electrical joiner and an unillustrated electrode of a subject electronic circuit board, serving as an object to be electrically interconnected, to thereby press the electronic circuit board with a pressure, causing elastic deformation in the electronic circuit board. Hence, the electronic circuit board and the subject electronic circuit board are interconnected electrically and softly with a plurality of conductive threads 3.
Prior art technical references include Japanese Patent Application Laid-Open Hei 9 No. 115577, Japanese Patent Publication Hei 7 No. 105174 and Japanese Patent No. 2796872.
The conventional press-contact electrical interconnector 17 is simply formed by using only a sponge silicone rubber, as described above, hence it has a feature that it easily sticks and lacks a slip property. Therefore, if the height of the electrical interconnector 17 is high, incorporation workability is deteriorated, and interconnection between the electronic circuit board and the subject electronic circuit board becomes very unstable, often causing non-conductivity. As a result, non-interconnection between the electronic circuit board and the subject electronic circuit board occurs, to thereby cause a big problem that the quality thereof cannot be stabilized.
Moreover, the conventional press-contact electrical interconnector is constructed as described above, and has a disposition pitch of the conductive threads 3 as narrow as 50 .mu.m to 100 .mu.m, and a diameter of each conductive thread 3 as small as 30 .mu.m to 40 .mu.m. Hence, even a small force applied to press the conductive threads 3 can cause deformation in the conductive threads, causing such a problem that the percent defective of products such as mobile phones becomes high. Furthermore, since the surface of the electrical interconnector 17 is easily deformed by only the application of a small force, the interconnection between the electronic circuit board and the subject electronic circuit board becomes very unstable, causing such a problem that it lacks incorporation workability.